Great Planes Piper J-3 Cub 40 Kit - GPMA0160 - Manual (Page 14)

the #7 rib. Align the top notch in the wing tip brace with the
#8 rib on the plans and glue the brace in place. Make sure
the “legs” of the brace are parallel with the spars.
❏ ❏
18. If you are currently building the left wing panel,
assemble the wing tips over the right wing panel plan. Place
the die-cut 3/16" balsa Wing Tip parts T1, T2 and T3
(CUB4W08) over the plans and check all joints for proper
fits. Sand the parts if necessary for good fitting joints. Pin
them in place and glue the pieces together with thin CA.
❏ ❏
19. Remove the Wing Tip from the building board and
inspect all the glue joints on the bottom side. Add thin CA to
all the tight fitting joints and add thick CA to all the open joints.
❏ ❏
20. Place the Wing Tip on a flat work surface and
lightly sand both sides flat and smooth.
❏ ❏
21. Sand the front edge of the Wing Tip to match the
angle of the LE. Test fit the wing tip into the slot at the front of
rib #7 and align the aft end of the wing tip with the aft end of rib
#7. Glue the wing tip to the LE, the wing tip brace and rib #7.
❏ ❏
22. Insert rib #8 into the notch in the wing tip brace so
the ends of the rib rest on the wing tip. Align the rib over the
plans and glue it in place. Sand the top and bottom outside
edges of the wing tip to remove the sharp corner where the
leading edge sheeting will be attached later.
❏ ❏
23. Install rib #2 by sliding it in between the spars and
twisting it into place. Center it on the LE and glue it with thin
CA. Do not glue it to the spars yet! Note: Maintain a 1/16"
gap between the bottom edge of the rib and the work surface
to allow for the center sheeting which will be installed later.
Use a scrap piece of 1/16" balsa to hold the rib up off the
work surface.
❏ ❏
24. Securely glue eight (six for the clipped wing Cub)
of the pre-cut 1/16" x 2-7/8" x 1-7/16" balsa vertical grain
shear webs (CUB4W20) to the rear surface of the spars,
starting between the two #5 ribs near the wing tip end of the
wing and working towards the center of the wing. Medium or
thick CA works best for this. Securely glue a shear web to
the front surfaces of the spars in the two rib bays between
the #3 ribs as shown in the next photo.
❏ ❏
25. Install the 1/8" x 1/4" x 33-1/2" balsa Top Forward
Spar (CUB4W12) in the forward rib notches, starting with
the #7 rib. Press the spar down firmly into the notches and
glue it in place with thin CA. Trim the forward spar and LE
even with the inboard side of the #2 rib and even with the
outboard side of the #7 rib.
❏ ❏
26. Position four 1/4" x 3/8" x 1-1/2" balsa Hinge Blocks
(CUB4W21) against the Outboard TE at the locations shown
on the plans and glue them in place with CA. Notice that they
are centered vertically on the outboard TE and not placed
down against the bottom TE sheeting.
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